Why does everything have to be online today?

Why do I have to today z.b. At my laptop first create an account on the Internet with everything works. Why is everything today only online?

Online processing saves staff (unfortunately, one sometimes wants to say).
It also provides a strong means of control and often involves the - more or less forced - possibility to send advertising to the user.

Because you bought the software when you bought a laptop. And that includes the regular updates.

Do not you have to, quite simply. With Windows 10 you can also log in as normal as before was default with a local account.

Logging in through a Microsoft account is not enforced, but it does bring some nice "features" with it, depending on which angle you look at.